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Friday, July 29th 2011, 12:46am

Newfoundland Class DDs for WW2

Newfoundland Class, Canadian Destroyers laid down 1940

Background : My Newfoundland Class DDs are based on the successful US Fletcher Class (1939).They are roughly the same size (2800 t vs. the Fletcher’s 2500 t) and one knot slower (35 knots). The Newfoundland’s have been designed with better maneuverability and sea-keeping in mind, and is perhaps the best of any destroyer class. The class sports the same flush-deck hull as the Fletchers, but a raised freeboard for better operations in inclement weather. They pack a gun armament of five 5-inch guns, twenty 40mm guns and ten 20mm guns to ward off any enemy aircraft, and a heavy ASW weapon suite consisting of a single quad-torpedo launcher in a center rotating tube, depth charge racks at the ship’s stern, and 3 Squid-style ASW mortar launchers. They are fast, hard-wearing, pack a powerful punch, and ready to tackle the Pacific campaign against Japan.

Displacement: 2,165 t light; 2,312 t standard; 2,592 t normal; 2,816 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
(367.00 ft / 360.00 ft) x 40.00 ft x (14.00 ft / 14.83 ft)
(111.86 m / 109.73 m) x 12.19 m x (4.27 m / 4.52 m)

Gun Armament:
5 - 5.00" / 127 mm 38.0 cal guns – 54.00 lbs / 24.49 kg shells, 300 per gun
Dual purpose guns in deck and hoist mounts, 1950 Model
5 x Single mounts on centerline (evenly spread)
3 raised mounts

20 - 1.57" / 40.0 mm 60.0 cal guns - 2.14 lbs / 0.97 kg shells, 2,000 per gun
Anti-air guns in deck and hoist mounts, 1950 Model
5 x 2 row quad mounts on sides (evenly spread)
2 raised mounts

10 - 0.79" / 20.0 mm 70.0 cal guns - 0.26 lbs / 0.12 kg shells, 2,000 per gun
Anti-air guns in deck and hoist mounts, 1950 Model
10 x Single mounts on sides, evenly spread
4 raised mounts

Weight of broadside 315 lbs / 143 kg

ASW Armament:
• Torpedoes: 4 - 20.0" / 508 mm, 29.50 ft / 8.99 m torpedoes - 1.823 t each, 7.290 t total
o In 1 quadruple-set deck mounted center-rotating launcher

• Depth Charges: 20 - 200.00 lbs / 90.72 kg Depth Charges + 10 reloads - 2.679 t total
o In Stern depth charge racks

• Mortars: 9 - 440.00 lbs / 199.58 kg trainable AS Mortars (Squid-type) + 12 reloads - 4.125 t total
o In 3 sets of triple-tube launchers located on aft deck aft

Armor:

- Torpedo Bulkhead - Strengthened structural bulkheads:
1.50" / 38 mm 234.00 ft / 71.32 m 12.00 ft / 3.66 m
Beam between torpedo bulkheads 30.00 ft / 9.14 m

- Gun Armor: Face (max) Other gunhouse (avg) Barbette/hoist (max)
Main: 0.80" / 20 mm - 0.80" / 20 mm

Machinery:
• Oil fired boilers, steam turbines,
• Geared drive, 2 shafts, 38,930 shp = 35 knots
• Range 6,000 nm @ 15 kts
• Bunker at normal / max displacement = 280 tons / 503 tons (Fuel Oil)

Wartime Complement: 181 - 236

Cost: £1.863 million / $7.451 million

Distribution of weights at normal displacement:
• Armament: 158 tons, 6.1 %
o Guns: 95 tons, 3.7 %
o Weapons: 63 tons, 2.4 %
• Armor: 167 tons, 6.4 %
o Torpedo bulkhead: 156 tons, 6.0 %
o Armament: 11 tons, 0.4 %
• Machinery: 931 tons, 35.9 %
• Hull, fittings & equipment: 834 tons, 32.2 %
• Fuel, ammunition & stores: 427 tons, 16.5 %
• Miscellaneous weights: 75 tons, 2.9 %
o Hull above water: 25 tons
o On freeboard deck: 25 tons
o Above deck: 25 tons

Overall survivability and seakeeping ability:
• Survivability (Non-critical penetrating hits needed to sink ship):
o 1,993 lbs / 904 kg = 31.9 x 5.0 " / 127 mm shells or 0.4 torpedoes
• Stability (Unstable if below 1.00): 1.26
• Metacentric Height (GM): 1.9 ft / 0.6 m
• Roll Period: 12.1 seconds
• Steadiness - As gun platform (Average = 50 %): 50 %
- Recoil effect (Restricted arc if above 1.00): 0.35
• Seaboat quality (Average = 1.00): 0.89
Hull Form Characteristics:
• Hull has a flush deck, a normal bow and small transom stern
• Block coefficient (normal/deep): 0.450 / 0.461
• Length to Beam Ratio: 9.00 : 1
• 'Natural speed' for length: 25.42 kts
• Power going to wave formation at top speed: 67 %
• Trim (Max stability = 0, Max steadiness = 100): 56
• Bow angle (Positive = bow angles forward): 5.45 degrees
• Stern overhang: 5.00 ft / 1.52 m
• Freeboard Breakdown (% = length of deck as a percentage of waterline length):
Fore end, Aft end
- Forecastle: 20.00 %, 21.00 ft / 6.40 m, 18.00 ft / 5.49 m
- Forward deck: 30.00 %, 18.00 ft / 5.49 m, 15.00 ft / 4.57 m
- Aft deck: 35.00 %, 15.00 ft / 4.57 m, 13.00 ft / 3.96 m
- Quarter deck: 15.00 %, 13.00 ft / 3.96 m, 13.00 ft / 3.96 m
- Average freeboard: 15.64 ft / 4.77 m

Ship Space, Strength and Comments:
• Space - Hull below water (magazines/engines, low = better): 175.7 %
- Above water (accommodation/working, high = better): 130.4 %
• Waterplane Area: 9,399 square feet or 873 square meters
• Displacement Factor (displacement / loading): 108 %
• Structure weight / hull surface area: 62 lbs/sq ft or 304 kg/sq meter
• Hull Strength (Relative):
o Cross-sectional: 0.83
o Longitudinal: 2.51
o Overall: 0.93
• Cramped machinery, storage, compartmentation space
• Excellent accommodation and workspace room
• Poor seaboat, wet and uncomfortable, reduced performance in heavy weather

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Friday, July 29th 2011, 1:14am

The immediate thing that sticks out is the poor seaboat quality of the design. I think you need to get that above 1.0; you have some reserve strength with which to do so.

Secondly I think the Squid mortars are right out for a design laid down in 1940, and a waste for a destroyer. A DD of this size will not have a primary mission of hunting submarines.

3

Friday, July 29th 2011, 1:23am

I disagree with the seaboat quality. SS has a horrible system of determining seaboat quality, which is somewhat dependent on maximum speed. This ship would be perfectly fine if you kept the max speed at 31 knots. SSs seaboat comparison scale is way out of whack, and isn't really a good reference for destroyers.

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Friday, July 29th 2011, 1:38am

Quoted

Originally posted by TexanCowboy
I disagree with the seaboat quality. SS has a horrible system of determining seaboat quality, which is somewhat dependent on maximum speed. This ship would be perfectly fine if you kept the max speed at 31 knots. SSs seaboat comparison scale is way out of whack, and isn't really a good reference for destroyers.


But he speciified the speed as 35 knots, and at that speed the seaboat quality is terrible. The software we use is the software we use; foibles and all.

5

Friday, July 29th 2011, 1:53am

I've generally used seakeeping at a lower speed as "maximum speed during all but light seas"